Electroosmotic Flow Suppression and Its Implications for a Miniaturized Full-Field Detection Approach to Capillary Isoelectric Focusing (cIEF)

Application of a full-field detection approach to a biological sample separation scheme known as capillary isoelectric focusing (cIEF) has yielded detailed spatial and temporal information about the transport processes associated with this technique, as well as the efficiency of this separation scheme. The full-field cIEF detection technique utilizes an illumination source such as blue light emitting diodes or a mercury arc lamp, microscope objectives, and a charged-coupled device (CCD) camera to image fluorescently labeled proteins and peptides. Interest in this approach arises from the ability to collect, in real time, information from the entire length of the separation channel. This full-field detection eliminates the need for flow mobilization and aids in the empirical analysis of the separation process. In an effort to optimize a miniaturized cIEF system, the full-field detection approach was used as a diagnostic to gauge the effect of varying the channel wall surface charge distribution.